package org.myorg; 

import java.io.IOException; 
import java.util.*; 

import org.apache.hadoop.fs.Path; 
import org.apache.hadoop.conf.*; 
import org.apache.hadoop.io.*; 
import org.apache.hadoop.mapred.*; 
import org.apache.hadoop.util.*; 

public class WordCount { 

   public static class Map extends MapReduceBase implements Mapper<LongWritable, Text, Text, IntWritable> { 
     private final static IntWritable one = new IntWritable(1); 
     private Text word = new Text(); 

     public void map(LongWritable key, Text value, OutputCollector<Text, IntWritable> output, Reporter reporter) throws IOException { 
       String line = value.toString(); 
       StringTokenizer tokenizer = new StringTokenizer(line); 
       while (tokenizer.hasMoreTokens()) { 
         word.set(tokenizer.nextToken()); 
         output.collect(word, one); 
       } 
     } 
   } 

   public static class Reduce extends MapReduceBase implements Reducer<Text, IntWritable, Text, IntWritable> { 
     public void reduce(Text key, Iterator<IntWritable> values, OutputCollector<Text, IntWritable> output, Reporter reporter) throws IOException { 
       int sum = 0; 
       while (values.hasNext()) { 
         sum += values.next().get(); 
       } 
       output.collect(key, new IntWritable(sum)); 
     } 
   } 

   public static void main(String[] args) throws Exception { 
     JobConf conf = new JobConf(WordCount.class); 
     conf.setJobName("wordcount"); 

     conf.setOutputKeyClass(Text.class); 
     conf.setOutputValueClass(IntWritable.class); 

     conf.setMapperClass(Map.class); 
     conf.setCombinerClass(Reduce.class); 
     conf.setReducerClass(Reduce.class); 

     conf.setInputFormat(TextInputFormat.class); 
     conf.setOutputFormat(TextOutputFormat.class); 

     FileInputFormat.setInputPaths(conf, new Path(args[0])); 
     FileOutputFormat.setOutputPath(conf, new Path(args[1])); 

     JobClient.runJob(conf); 
   } 
} 

